CLI virtual import bug

The following SMS mapping works fine ..

MAPPING
FROM CSV { }
TO {
?source_iri a :Xxx .
?source_iri :description ?desc ;
:name ?source_name ;
... }
WHERE {
BIND(TEMPLATE("https://example.com/{source}") AS ?source_iri)
BIND(StrDt(sourceField("description"), xsd:string) AS ?desc)
BIND(StrDt(sourceField("name"), xsd:string) AS ?source_name)
... }

But, if I change the variable, source_name, to name .... I get an import error:

Error importing file '/Users/andreaw/Downloads/source-details.csv'. Server Error (java.lang.NullPointerException), check logs for details

The log entry is very vague, failing at:
com.google.common.base.Preconditions.checkNotNull(Preconditions.java:889) ~[guava-31.1-jre.jar:?]

Andrea